King Kai

Three minutes later, He-El arrived at his destination and saw King Kai's Planet. King Kai's Planet was tiny, only thirty-six meters in diameter. Yet its gravity was ten times that of Earth. Based on its thirty-six-meter diameter and the law of universal gravitation, using the knowledge he currently possessed, He-El deduced that King Kai's Planet had roughly one one-hundred-and-twenty-five-trillionth of Earth's mass and three-and-a-half million times Earth's density.